There are phase locked loops (PLL) (phase synchronization circuits) in which feedback control is performed based on periodic signals that are input and signals whose phases are synchronous are output from internal oscillators.
Oscillators for the PLLs are implemented by, for example, voltage-controlled oscillators (VCOs).
For example, there is a known technology in which LC-resonant voltage-controlled oscillators are used as VCOs and inductance components of connection lines between oscillation nodes thereof are relatively reduced or injection locking is performed to cause oscillation of the LC-resonant oscillators (see, for example, Japanese Laid-open Patent Publication No. 2007-82158).
In the related art described above, however, in a configuration in which a reference signal from an oscillator is distributed to a plurality of PLLs, there is a problem in that, for example, a phase mismatch occurs between the output signals of the PLLs when characteristics of the oscillators in the PLLs vary.